1. Field of the Invention
The present invention relates to beverage forming and dispensing systems. More particularly, the present invention relates to beverage forming and dispensing systems for effectively preparing a beverage mixture from concentrate, and even more particularly to beverage forming and dispensing systems for effectively preparing a tea beverage mixture from concentrate.
2. Description of the Related Art
Beverages formed from concentrates are enjoyed around the world. An important advantage of forming a beverage from a concentrate is that only the concentrate need be shipped to the dispensing site; any available water supply at the site can be used to form the bulk of the final mixed product. An advantage in forming traditionally brewed drinks, such as tea and iced tea, from concentrate is that the time-consuming brewing process is eliminated.
There are many types of beverage making machines or appliances for forming beverages from concentrate. For example, U.S. Pat. No. 4,920,871 relates to a beverage making appliance in which hot water is discharged onto a brewing material, such as ground coffee or tea leaves, placed in a filter within a brewing funnel. In making iced tea, a brewed concentrate discharges from the brewing funnel and combines with cold water to form an iced tea stock. However, in this beverage-making appliance, the concentrate must first be brewed and the ratio of the cold water and hot water concentrate is not precisely metered.
U.S. Pat. Nos. 4,309,939 and 4,579,048 relate to beverage brewing apparatuses in which beverage concentrate is first brewed from a dry beverage making material in a funnel. The concentrate is distributed into a reservoir into which cold water is added to dilute the concentrate to an acceptable strength. However, the cold water is supplied to the reservoir after the hot concentrate begins to flow into the reservoir. Accordingly, the cold water and hot concentrate may stratify in the reservoir and not mix sufficiently.
U.S. Pat. No. 5,579,678 relates to an apparatus for automatically sweetening tea in which heated water combines with tea in a brewing station to form tea concentrate where it is mixed in a canister with a delivered sweetener. After sufficient tea concentrate is brewed and delivery of the sweetener is completed, a quantity of diluting water is mixed with the hot tea concentrate and dissolved sweetener. Because the diluting water is supplied after a complete batch of tea concentrate is brewed, the resulting mixture may stratify and not mix sufficiently. It is known to agitate a mixture for prevention of stratification and for more effective mixing. However, more complicated structure and greater power consumption is necessary to effect agitation.
Additionally, conventional leaf tea urns are costly to clean and operate, and are subject to undesirable and even dangerous growth of bacteria inside the urn. The tea itself is a food source for bacteria and the long residence times of tea product in the urn create an environment that promotes bacteria growth. Generally, bacteria colonies start to reproduce within several hours of making a fresh batch of tea. Typical post mix iced tea systems negate the disadvantages of the leaf tea brewing process by directly mixing tea syrup with cold water. However, since there is no brewing step, the finished tea product does not have the same visual and taste quality as real, fresh-brewed iced tea.
Typical post mix beverage syrup systems utilize sold out devices such as pressure switches to determine when the syrup concentrate is depleted. However, pumping rates for conventional systems are much higher than those encountered with a low pressure system, such as for a tea concentrate. In a conventional system, typically 15 ml per second of syrup concentrate are provided, and gas pumps are used to deliver the syrup. The pressure in the bags is 0 psig, and the pump draws syrup out of the bags and discharges it at pressures on the order of 60 psig. When the bag empties, the discharge pressure from the pump will drop to near 0 psig, and a switch opens to prevent further dispensing. In low pressure tea concentrate systems, a peristaltic pump is used to deliver low flow rates, typically 1.0 ml/sec, and with ability for precise metering. However, the conventional pressure switches are not suitable for detecting a sold out condition when the concentrate is delivered with a peristaltic pump, because the pump discharge pressure is typically less than 1.0 psig, which is outside of the sensitivity range of the pressure switch.
From the foregoing, it is apparent that there is still a need for an improved method and apparatus for automatically preparing beverages from concentrate and ensuring that the resulting beverage mixture is sufficiently mixed. It is also apparent that there is still a need for an improved method and apparatus for sensing a sold out condition of a concentrate in a low pressure type system.